If you think volcanoes played a big role in the mass extinction that killed the dinosaurs, you’re wrong. As a matter of fact, a Yale-led team of researchers has revealed that the asteroid bore far more responsibility than we previously realized.
In a recent study, Yale assistant professor of geology and geophysics Pincelli Hull and her colleagues illustrated that environmental shocks from volcanic eruptions in Deccan Traps, India occurred prior to the Cretaceous-Paleogene extinction event 66 million years ago. This allowed them to conclude that such volcanic activity did not contribute to the mass extinction.
Most researchers recognize that K-Pg, the mass extinction event, happened after an asteroid crashed into the Earth. Some scientists have suggested that volcanoes played an important role in K-Pg because of the amount of volcanic activity we have evidence for around the same period.
“Volcanoes can drive mass extinctions because they release lots of gases, like SO2 and CO2, that can alter the climate and acidify the world,” said Hull, who also acknowledged that the latest research has centered on the “timing of lava eruption rather than gas release.”
To determine the timing of volcanic gas emission, the research team made a comparative analysis of the global temperature change and the carbon isotopes (an isotope is an atom with differing mass and physical properties) from marine fossils with models of the climatic changes of carbon dioxide release. Their findings show that the major CO2 releases occurred prior to the asteroid impact, meaning the asteroid was the sole cause of K-Pg.
Michael Henehan, a former Yale researcher who collected the temperature records for the study, said that the volcanic eruptions that took place in the late Cretaceous period led to steady global warming (of around two degrees), but not the mass extinction of dinosaurs. Hull explained that several species shifted toward the north and south poles due to the warming, but this did not alter the effect of the asteroid blast.
Meanwhile, recent work in the Deccan Traps region of India has found that enormous eruptions occurred in the aftermath of the mass extinction. These results have confused researchers because there is no warming incident to match.
“The K-Pg extinction was a mass extinction and this profoundly altered the global carbon cycle,” suggested Yale postdoctoral associate Donald Penman, the study’s modeler. He explained that their findings imply that such changes would enable the sea to absorb a massive amount of CO2 on longer scales, possibly “hiding the warming effects of volcanism in the aftermath of the event.”
Besides Yale University, The International Ocean Discovery Program and the National Science Foundation assisted in funding the study.